An article from the Washington’s Blog
Guest Post: It’s Not Just Alternative Energy Versus Fossil Fuels or Nuclear – Energy Has to Become DECENTRALIZED
Posted: 20 Apr 2011 11:11 PM PDT
Proponents for oil, gas, nuclear and coal claim that we must expand these risky and oftentimes deadly types of energy production, or we will shiver in the dark like cavemen.
Proponents of alternative forms of energy say we should switch over to cleaner fuels to avoid a parade of horribles … and point to the Gulf oil spill, the Japanese nuclear crisis and the destruction of aquifers with natural gas fracking as examples. Defenders of fossil fuels and nuclear rebut this by saying that alternative energy isn’t ready for prime time yet.
As I’ll show below, the question is not as simple as it may sound.
Return on Investment
As Thomas Homer-Dixon, director of the Trudeau Center for Peace and Conflict Studies at the University of Toronto, notes:
A better measure of the cost of oil, or any energy source, is the amount of energy required to produce it. Just as we evaluate a financial investment by comparing the size of the return with the size of the original expenditure, we can evaluate any project that generates energy by dividing the amount of energy the project produces by the amount it consumes.
Economists and physicists call this quantity the “energy return on investment” or E.R.O.I. For a modern coal mine, for instance, we divide the useful energy in the coal that the mine produces by the total of all the energy needed to dig the coal from the ground and prepare it for burning – including the energy in the diesel fuel that powers the jackhammers, shovels and off-road dump trucks, the energy in the electricity that runs the machines that crush and sort the coal, as well as all the energy needed to build and maintain these machines.
As the average E.R.O.I. of an economy’s energy sources drops toward 1 to 1, an ever-larger fraction of the economy’s wealth must go to finding and producing energy. This means less wealth is left over for everything else that needs to be done, from building houses to moving around information to educating children. The energy return on investment for conventional oil, which provides about 40 percent of the world’s commercial energy and more than 95 percent of America’s transportation energy, has been falling for decades. The trend is most advanced in United States production, where petroleum resources have been exploited the longest and drillers have been forced to look for ever-smaller and ever-deeper pools of oil.
Cutler Cleveland, an energy scientist at Boston University who helped developed the concept of E.R.O.I. two decades ago, calculates that from the early 1970s to today the return on investment of oil and natural gas extraction in the United States fell from about 25 to 1 to about 15 to 1.
This basic trend can be seen around the globe with many energy sources. We’ve most likely already found and tapped the biggest, most accessible and highest-E.R.O.I. oil and gas fields, just as we’ve already exploited the best rivers for hydropower. Now, as we’re extracting new oil and gas in more extreme environments – in deep water far offshore, for example – and as we’re turning to energy alternatives like nuclear power and converting tar sands to gasoline, we’re spending steadily more energy to get energy.
For example, the tar sands of Alberta, likely to be a prime energy source for the United States in the future, have an E.R.O.I. of around 4 to 1, because a huge amount of energy (mainly from natural gas) is needed to convert the sands’ raw bitumen into useable oil.